The invention relates to a mobile shovel excavator with a superstructure which rotates around a vertical axis on an undercarriage, whereby the arc of the pivoting superstructure projects over the side of the undercarriage, and whereby a stump jib pivots around a vertical pivot axis by means of a hydraulic cylinder which is articulated on the superstructure, and at the outer end is found a pivot support for the sideways pivot of a vertically pivoting excavator jib.
With a shovel excavator of this construction, known in German Patent No. 26 12 879, a filler element is provided between the vertical axis of an attachment holder found on the super structure and the rear of the shovel excavator jib, by the connection of which ditches can be made on the far side of obstacles projecting from the undercarriage, e.g. on the far side of guide boards, ditches and so forth. The filler element is pivotable at 45.degree. angles to both sides from a middle setting on the longitudinal middle axis on the superstructure, with the aid of one single hydraulic cylinder.
The objective of the invention is to improve a mobile shovel excavator of the described known structure, such that the work members (digging tool, shovel arm, jib and stump jib) can be folded together in the narrowest possible space outside the field of view of the vehicle operator, and such that the center of gravity of the excavator is concentrated towards the middle of the superstructure.
This objective is attained in that stump jib is pivotable about approximately 90.degree. from an end position which is essentially transverse to the longitudinal middle axis of the superstructure and is still within the arc of the superstructure. Also, a repository platform is provided on the superstructure on the side corresonding to said end position of the stump jib and from the opposite superstructual elements, on which platform the digging tool can be deposited with the excavation jib pivoted back parallel to the longitudinal axis of the superstructure.
By means of this proposal, with stump jib pivoted to its side end position and the excavator jib pivoted approximately 90.degree. in the same direction, and by folding up of jib and shovel arm it is possible to accommodate these working members including the digging tool, within the arc subscribed by the superstructure, so that even with limited workspace, e.g. within a narrow alley, the excavated material carried in front of the excavator can be discharged on a cargo vehicle standing behind the excavator. In the travelling mode, the digging tool is lowered and tightened on the repository platform, after having sidewardly pivoted the stump jib and rearwardly pivoted the excavator jib, so that the working members, which afford a satisfactory range of action, are folded up compactly and are brought and accomodated within the arc circumscribed by the superstructure. As the stump jib at its maximum pivot angle extends essentially only to the longitudinal middle axis of the superstructure, and as the operator cab is arranged towards the side opposite to the stump jib's pivot range side, the view of the operator remains unobstructed both in the traveling operation and in the excavating operation. Particularly in driving the vehicle with the stump jib pivoted sideways, the view of the operator is not obscured by any of the working members, so that the excavator can be used in open streets within the legal regulations as a fast-moving vehicle, moving rapidly from one construction site to the next. Prerequisites for rapid street travel are met in that the weights of the different working members in their folded up state are efficient only within the arc of the superstructure and thereby bring the center of gravity into the middle of the superstructure. For pivoting the stump jib within a preferrably limited pivot angle of approximately 90.degree., one single simple hydraulic cylinder will suffice.
It is proposed that when the superstructure is set in direction of movement, the repository platform is found within the outside dimension to the side of the undercarriage. Thus the digging tool, by pivoting of the stump jib and of the excavator jib, can be so lowered on the repository platform and so arranged that it does not project sideways beyond the undercarriage. However, for discharge of excavated material when there is little space, the excavator jib need not be brought above the platform but will be pivoted just so far that the digging tool becomes located, with the excavated material still therein, within the arc circumscribed by the superstructure.
With one embodiment of the invention, the excavator jib, with the aid of a pivot mechanism consisting of two cylinders or a reversible motor, can be pivoted at the end of the stump jib around at least 90.degree. relative to the longitudinal axis of said stump jib. Powered operation of the side pivot of the excavator jib is not absolutely required, since because of the unlimited pivotabiity of the superstructure, the desired digging positions can also be reached if the excavator jib remains tightly set at certain angular positions relative to the stump jib.
If, as is known with shovel excavators, the operation stand is found at the front and to one side of the superstructure, then in another construction of the invention, the pivot axis can be set on the stump jib attachment holder so far back in the arc that the sideways pivoted stump jib lies outside the clear view angle between the operator and the front end of the undercarriage. Because the operator has not only free view forward but also beyond the front end of the undercarriage, the view and also the maneuverability of the excavator is decidedly improved. Furthermore, a housing coping of a power unit housing, arranged between repository platform and operator cab, can be configured as an additional repository platform for excessively wide trenching tools. Thereby a wider digging shovel, which would project sideways over the support platform and also over the outside dimensions of the undercarriage, with an additional pivot of the excavator pivot of the excavator jib, goes further inward and then if the jib is raised, is let down on the housing coping. The repository platform can also be used as transporter for additional digging tools which the excavator carries along to its work place.